Control mechanism for power actuated brakes



Feb. 14,1939. BI D|K 2,146,803

.CONTROL MECHANISM FOR POWER ACTUATED BRAKES INVENTOR BURNS DIC K Feb. 14, 1939. B. DICK 2,146,803

CONTROL MECHANISM FOR POWER ACTUATED BRAKES INVENTOR EUR DIC K ATTogEY E Paci/ccd Feb. 14, 1939 PATENT ol-FlcE .CONTROL MECHANISM FOR POWER y AOTUATED BRAKES Burns Dick, Ferguson, Mo., assignor to Warner Electric Corporation, St. Louis, Mo., a corporation o! Delaware application august as. 1931,' semi Nc. 161,391 11 emma (c1. 19e-1s) My invention relates to power brakes and more particularly to means for holding the brakes in applied position under certain conditions. One of the objects o! my invention is to provide improved means for holding iluid power brakes in applied position .by a predetermined pressure which. isaautomatically eil'ective only when the vehicle is stopped and power is not being applied to the vehicle wheels.

Another object of my invention is to provide gravity-controlled means for automatically maintaining eithervacuum power brakes or air pressure power brakes applied when the vehicle is stopped.

Other objects will become apparent from the following description taken in connection with the accompanying drawings in which Figure 1 is a schematic view of an air pressure actuated braking mechanism and clutch control mechanism showing my invention associated therewith,` parts being in cross section; and Figure 2 is a` schematic view of a vacuum-operated braking mechanism and clutch control mechanism showing my invention associated therewith, parts being in cross section.

l Referring to Figure 1 in detail, the numeral I indicates the usual cross shaft of a motor vehicle which is adapted to actuate the wheel braking mechanism in a well-known manner. The shaft o I is provided with an actuating arm 2 which is connected by means of a rod 3 with the piston l of a power cylinder 5, the latter member being pivoted to a stationary part of the vehicle chassis. The arm 2 also has pivoted thereto a rod 5 which is secured to a valve casing 1 by means of the casing bracket 1. The valve shown by way of example is a combined follow-.up and metering valve which is Aadapted to control the application and exhaust of air under pressure to the cylinder 5 but other types of control valves may be employed i! desired. Slidably mounted in the valve casing is a rod 8 in alignment with rod 6. this rod being connected by means of a rod 9 with the brakeV pedal III. It is thus seen that valve casing 1 is supported in a suspended position on rods 6 and l which are permitted to have relative movement for controlling the valve elements within the casing, the controlling element beiuganarmll carriedbyrod 8. The application valve I2 is normally biased to Y the closed position by spring I3 in the applica".

'tion chamber Il' which is in communication with a second chamber I5 by means of openings I6 controlled by valve I2. The stem of valve I2 n extends within chamber I5 and is provided with open position by arm II when a piston I1. A second spring Il is interposed between the valve stem and the actuating arm II. *rnc chamber l5 is connected by a conduit l5' with the power cylinder 5 and it also communicates with the exhaust chamber I9 located on 5 the rear side of arm II. The exhaust chamber is provided with an exhaust valve 20 normally biased to closed position by meansvoi the spring 2|, this valve controlling the openings 22 leading to the atmosphere through chamber 23. The ex. 10

haust valve 2li is provided with. a stem extending to a point adjacent arm II.

The application chamber Il is connected by a conduit 24 to a suitable source of power which in this instance comprises apressure tank 25 and 15 an air compressor 25. This air compressor' isshown as a separate unit but may be driven directly by the vehicle engineer by a lsuitable suction motor operated -from the intake manifold of the engine.

InA operation of the above described braking system the exhaust valve 2l is normally held in the brake pedal I5 is in its inoperative position, this condition being caused by spring 21 between the valve 25 casing and rod 5 which normally biases rod l and its attached arm II to its extreme right position. Upon actuation of the brake pedal I0 to apply the` brakes, rod I is moved relatively to the valve casing permitting exhaust valve 20y to 30 close and causing arm II to compressv spring I8 and force the application valve I2 to open position, thereby admitting iiuid under pressure from v the pressure tank 25 to the power cylinder 5 and causing rotate the cross shaft land apply pressure to the brakes. The movement o! arm 2 by means of piston 4 and connecting rod 6 will cause the valve casing to follow-up" the movement of rod 8, thuspermitting the application valve I2 to 40 close, the exhaust valve 2l remaining closed. Further movement of brake pedal I0 will again open the application valve and admit additional air under pressure to the power cylinder to apply further pressure to the brakes with the same 45 follow-up action of thel valve casing.

When the brake pedal III is released, spring 21 will cause rod i to be moved relatively to the valve casing and open exhaust valve 2l to re- .lease the air in the power cylinder 5. said valve 50 remaining open until it is desired to again apply the brakes.

The piston I1 in chamber I5 prevents an excess oi air under pressurefrom entering the power cylinder when the application valve is piston l to be moved to the left to 35 open since the pressure in chamber I8 will cause the piston to move to the right against the action of spring I8,l thereby closing valve l2. In case of failure of the power system, rod 8 is provided with a shoulder 28 whereby shaft I may be adJustable shoulder 38 cooperating with a spring,

31 for holding the valve element 34 seated. The valve"element opens toward theatmosphere and theV pressure necessaryto open the valve may be predetermined by proper adjustment of shoulder 38 on the valve stem. It is thus seen that by means of this valve only a predetermined amount of air canbe exhausted from'lthe power, cylinder' when 1the exhaust valve 29 of ,the control valve mechanism is in ,a positionto. permit the air to be exhausted. 'L'hus with valve 34 closed f under a predetermined spring pressure, the brakes can be held applied by a pressureetermined by the valve "mechanism" 30. Therefore,y notwithstanding the fact that the brakeLpedal has been released to perriit release of the'brakes, the brakes, nevertheless, can be maintained applied to hold the vehicle from rolling on any inoline upon which the vehicle may have been stopped. t

' In accordance ,with my invention I also con#-Y trol the valve mechanism 30 by lmeans of theclutch mechanism.' on the vehicle. The' 'casing 3| is provided with a suitable arm 38 upon which 48 overlying the stem of the valve element 34 and another arm 4| connected to the clutch pedal 42 bymeans of a link 43. The arm 38 ,also has pivotally mounted thereon, coaxially with lever 38, a pendulum 44 which is normally held in engagement with the stop 48 on the valve casingv by means of a very light springl 48. 'Ihe top portion of the pendulum carries a pin 41 which extends into a slot 48 of lever 38, thus resulting in a mechanism whereby tire pendulum can rotate lever 38 in a clockwise direction but permitting the lever 38 to be moved in a clockwise direction without movement of thek pendulum. 'I'he connection between lever 38 and the clutch pedal isl such that when the clutch is disengaged (as shown inv Figure 1) and the pendulum is against stop 48, valve element 34 will be closed. yWhen the clutch is in engaged position lever 39 will be swung in a clockwise direction and thus spring 31.

In operation when the vehicle is moving along a highway and the clutch is engaged, the brakes may be applied and released at will by actuation of the brake pedal since valve 34 under these conditions will be held open by arm 38. If the clutch should be disengaged under these conditions, the brakes may still be applied and released by operation of the brake pedal since valve 84 will be held in open 'position by pendulum 44 since thedeceleration of the vehicle by the application of the brakes will result in the pendulum swinging forwardly and by pin 41 operate u lever 38 to hold valve element 34 open. If the is pivotally mounted a lever 38 having one arm open valve element 34. against the action ofvehicle should be brought, to ay stop facing upwardly on an inclined roadway and the brakes applied or held applied, the brakes will automatically be rmaintained applied under a predetermined pressure determined by valve 34 and without the necessity of holding ther brake pedal depressed. Under theser conditions the clutch will be disengaged, the pendulum will be against stop 45, and valve 34 will be closed as shown in Flgurel. If the brakes have been applied with pressure greater than that which can be held in the system by valve 34, `the excess pressure will be released to atmosphere through valvev 34 as soon as the main control valve permits the air under pressure in the power cylinder to be released.

From the foregoing it is seen that by means of the improved brake holding mechanism only a predetermined amount of pressure is ,maintained in the brake lines when it is desired to hold the vehicle stopped on an incline.l Thus there is no strain on the braking system which would be present if the brakes were held applied under excessive pressure which may have been used to stop the vehicle. Also, by controlling the pressure relief valve by means of the pendulum, there is no danger of the relief valve being operated during deceleration of the vehicle whereby the brakes may become tied up". By having the brake holding means embodied in a braking system/in the manner disclosed, there is no necessity for the operator to hold the brake `pedal in br'ake applied position when the vehicle isy stopped in order to prevent the vehicle from rolling backward and thus the operators rightoot is free to be used to operate other v oontrb members on the vehicle, as for example,

l the accelerator preparatory to starting or the starter pedal in the event the engine has become inoperative. The brakes are always automatica'lly released when the clutch is engagedv and` at the time that power is beginning to be applied to the vehicle wheels.

Referring to Figure 2, I have shown my inven- Vtion associated with a vacuum-operated braking l nected bymeans of a rod sito the plm n of the suction motor 51. The chamber of the suction motor ahead of piston 88 is connected by means of conduit 88 with the'control valve 88 which in turn is connected by conduit 88 with the manifold of the engine. 'I'he control valve shown is lo'f` weil-known constructiow'being attached to rod 8l which is connected to the lower arm of lever 84. 'I'he conduit 88 is in communication with valve chamber 82 and conduit 88 is in communication with valve chamber 83, these chambers being separated by the annular wall 84 and controlled by the valve diaphragm 88. This valve diaphragm is actuated by means of the annular valve element 88 carried by rod 81 connected to the usual vehicle brake pedal 88.

From the above structure itis readily seen that when the brake pedal 88 is depressed, element 88 will ilex the valve diaphragm 88, thereby placing chamber 82 in communication with chamber 83 and the suction motor in communication'with f the manifold, thus causing piston I8 to be moved n 'i sembly, means including a main control valve 4i'or to the right to apply the brakes. Since the control valve 59 is attached to brake rod 6I, the valve diaphragm will be seated by the followup action of rod 6I. Additional movement of the brake pedal will again unseat the diaphragm and cause additional pressure to be applied to the brakes. Release of the brake pedal unseats valve element 66 and places conduit 58 in communication with the atmosphere through the port 69. thereby releasing the brakes. In order to provide-for manual actuation of the brakes in case of failure of the power means, rod'61 is provided with a shoulder 10 for engagement with the valve casing whereby the brake lever 5l may be directly actuated.

In accordance with my invention the port 69 communicates with a conduit 1| which is connected to a. pressure reliefvalve mechanism 12.

-This valve mechanism comprises a casing 13 having an opening 14 communicating with the atmosphere, the opening being controlled by a valve element 15 mounted upon a valve stern' 16 which extends to the exterior of the valve casing. A spring 11 normally biases the valvey element 'I5 to closed position, thus preventing air under atmospheric pressure from entering the valve casing except whenv the pressure differential is of a predetermined value. The valve stem 16 is controlled by the clutch mechanism and a pendulum in identically the same manner as the valve stem shown in Figure l and it is not believed necessary to describe this structure in detaill reerence being had to the previous description.

In operation when the vehicle is moving along a roadway with the clutch engaged, the brakes may be applied and released at will since under these conditions the valve element 15 will be unseated by the engaged condition of the clutch. If the clutch should be disengaged, valve element 15 would still be maintained in open position when the brakes are applied sincethe pendulum will swing forwardly under the action of inertia and maintain the valve open. When the vehicle is brought to a stop facingupwardly on an inclined roadway .and the clutch is disengaged, as shown in Figure 1, the brakes. may befapplied and held applied under predetermined pressure without maintaining the foot on the brake pedal. Under these conditions the valve element 15 will be free to be seated by the action of spring 11 and also the main control valve,59 will be in a position to permit air under atmospheric pressure to enter the suction motor 51,*the amount of air admitted, however, being determined by spring 11. When it is desired to start the vehicle, release of the clutch will cause the valve element 15 to be unseated and atmospheric pressure can enter the suction motor to release the brakes. It is thus seen that the structure disclosed in Figure 2 with respect to the suction-operated brake prodces the same results as the structure shown in Figure 1.

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principles 'of my invention, I do not intend that its scope be limited except as set forth by claims. v

Having fully described my invention, what I claim as new and desire to secure by, Letters Patent of the United States is:

1. In a motor vehicleaprovided with a braking assembly, a iluid pressure operated motor comprising amovable element for actuating the asthe appended causing fluid pressure to act on the movable element of the motor and for connecting the motor to the atmosphere to cause it to be inoperable,

other valve means associated with said means and positioned in the atmosphere connection from the main control valve for maintaining an elective operating iluid pressure acting on the movable element of the iluid motor notwithstanding said main control valve has beenvmoved to a position normally permitting said fluid motor to be inoperative, and means operative under the action of inertia during deceleration of the vehicle for causing. said second named valve means to be inoperative and under the action of gravity associated with said means and positioned in the atmosphere connection from the main control valve for maintaining an effective operating uid pressure acting on the movable element of the uid motor notwithstanding said main control valve has been moved to a position normally permitting said fluid motor to be inoperative, means operative under the action of inertia during deceleration of the vehicle for causing said second named valve means to be inoperative and under the action of gravity when the vehicle is stopped for permitting said second named valve means to be operative, and means controlled by the clutch mechanism when in clutch-engaged-position for causing said second named valve means to be inoperative.

3. In a motor vehicle provided with a clutch mechanism and with a braking assembly, a uid pressure operated motor comprising a movable element for actuatingxthe assembly, means in. cluding a main control valve for causing fluid pressure to act on the movable element of the motor, other valve means associated with said means for-maintaining an eective operating fluid pressure acting on the 'movable element of the uid motor notwithstandinwriid main control valve has been moved to a position normally permitting said fluid motor to be inoperative, said other valve means embodying means for predetermining the value of said effective operating uid pressure, means operative under the action of inertia during deceleration of the vehicle for causing said second named valve means to be inoperative and under the laction of gravity when the vehicle is stopped for permitting said valve means to be operative, and means controlled by the clutch mechanism when in clutch-engaged lposition for causing said .second named valve l able element for actuating the braking assembly,

a'source of pressure connected to the fluid motor, a main control valve for admitting iluid under pressure to the iluid motor and exhausting it to atmosphere through a. conduit in constantcommunication Jwith the atmosphere, valve means associated with the exhaust conduit for preventing `the uid under pressure from being exhausted from the iiuid motor when so permitted by the main control valve, means governed by the action of inertia and the action of gravity for controlling said last named valve means, and means for causing said last named valve means to be ineiective when the clutch mechanism is in clutch-engaged position.

6. In a motor vehicle, a clutch mechanism, ai braking assembly, a fluid motor including a movable element for actuating the braking assembly, a source ci pressure connected to the uid motor, a main control valve for admitting iiuid under pressure tothe fluid motor and exhausting it to atmosphere through a conduit, pressure relief valve means associated with the exhaust conduit for preventing a predetermined amount of the iluid under pressure from being exhausted from the iluid motor when so permitted by the main cpntrol valve, means governed by the action of inertia and the action of gravity for controlling said last named valve means, and means for causing'said last named valve means to be inv eiective when the clutch mechanism is in clutchengaged position. I

7. In a motor vehicle, a braking assembly, a suction motor including a movable element for yactuating the braking assembly, a source of suction, a main control valve for connecting the suction motor to the source of suction or to the atmosphere through a conduit in constant communication with the atmosphere, valve means associated with the atmospheric conduit for preventing air from entering the suction motor when 'so permitted by the main control valve, and .means governed by the action of inertia and the action of gravity for controlling said last named valve.

named valve, andmeans for causing said last named valve means to be ineffective when the clutch mechanism is in clutch-.engaged position. 9. In a vehicle, a clutch mechanism, a braking "assembly, asuction motor .including a movable element for actuating the braking assembly, a source of suction, a main control valve for connecting thesuction motor to the source of suction lthe action of inertia and the action of gravity for controlling said last named valve, and means for causing said last named valve means to be ineilective when the clutch mechanism is in clutch-engaged position.`

10; In a motor vehicle provided with means for disconnecting the vehicle wheels from the source of power of the vehicles-nd with a braking as-' sembly, a fluid pressureoperated motor comprising a movable element for actuating the assembly, operator-operated means for causing fluid pressure to act on the, movable element, valve means for maintaining an effective operatingnuid pressure acting on said movable element notwithstanding said operator-operated means has been vmoved to an inoperative position, means, operative when the disconnecting means is effective to permit power to be applied to the vehicle wheels, for pausing saidvalve means to be inoperative, a pendulum associated with said last named means and adapted to cause said valve means to be inoperative as aresult of the action of inertia on the pendulum during deceleration of the vehicle but. only when the disconnecting means is in disconnected position.

11. In a motor vehicle provided with a clutch mechanism having a clutch pedal and with a `braking assembly, a iluid pressure operated motor ating iluid pressure acting on said movableelement Anotwithstanding said operator-operated means has been moved to an inoperativeposition, a bell-crank for operating said valve means, va connection between said bell-crank and the clutch pedal for causing said valve means to be ineiective when lthe clutch pedal is in clutchengaged position, a pendulum pivotslly mounted on the same axis as the bell-crank, and Va connection between said pendulum and the' bellcrank for causing said valve means to be inoperative as a result of the action of inertia on the pendulum during deceleration'ot the vehicle .but only when the clutch pedal is in clutch-disengaged position. f

BURNS DICK.. 

